Nichols, who heads the U.S. Naval Forces Central Command, 5th Fleet, said that within the last two weeks, ships stopped and searched two ships. In one instance, sailors detained one individual; in the other it was three.

In one case, the suspected al Qaeda was trying to enter Iraq. In the other, Navy officials do not know where the ship was destined.

At least one ship was carrying hashish, said Navy officials. They conjecture that al Qaeda is running drugs to pay for terrorist acts.

"We're having some success at that disrupting movement, not only of terrorists going into Iraq but other terrorist activities in the region," Nichols said. "Frankly, drugs and terrorists use the same network and stopping one will stop the other."

He would not say where the men are being held.

U.S. and coalition ships interdict terrorists and terrorist support that is flowing or finding its way into Iraq. What's more, the maritime interception program works against drugs and weapons of mass destruction also. The operation also puts a damper on oil smuggling out of Iraq.

Unless there is specific intelligence, most ships are simply queried by crews of frigates and destroyers enforcing the rules. Only some ships that fit the profile are searched, and a very small proportion is impounded.

Most interceptions occur in the Persian Gulf but, Nichols said, some also happen in the Gulf of Oman and in the Red Sea.